Air supply means and method for cupolas



R. 8. BROWN AIR SUPPLY MEANS AND METHOD FOR CUPOLAS Aug. 14, 1934.

Filed Nov. 9. 1931 5 Sheets-Sheet 1 [72 U678 2, 07" jigerfihccrf fimzwz/1 Aug. 14, 1934. R. s. BROWN AIR SUPPLY MEANS AND METHOD FOR CUPOLASFiled Nov. 9, 1931 3 Sheets-Sheet 2 Invemzfor fi oyerfizfmrf .Bmzwz Aug.14, 1934. R. 5. BROWN 1,970,221

AIR SUPPLY MEANS AND METHOD FOR CUPOLAS Filed Nov. 9. 1931 5Sheets-Sheet 5' 1720672250? Zggerfiaaamfrawr'a Patented Aug. 14, 1934 rv i UNITED PATENT V '1,9'70,2 2'1".; I V AIR se ia MEANS Ass stant FoRoUroLAs r Roger Stuart Brown,"Ch ioago,' Ill. Application November 9,1931, scram. 574,176

9 cla ms; (o1."2c 14) This invention relates to improvements in blastable inlet pipes Bwhich Communicate with the furnaces, and moreparticularly tocupolas. One bustle pipe B Assuming the connection withobject is to provide a durable, low cost, hot'bl'ast the usual blower,when the cupola is in operation cupola which will melt or smeltwithagreat econ and the blower starts to Ope it forces omy of fuel, orat a highertemperature, or with through the pipe B and the bustle pipe Bfor both results. For certainoompositions, melting distribution forexample through the nipples B at a higher temperature produces a bettergrade 130' th h at p p Order to p e of cast iron, probably due tothecomplete solustrain on the parts due to variations in ten1peration ofthe carbon at: the higher temperature. ture I may provide any suitableflexible connect- I 10" Another advantage is the possibility of meltinging m ans, f r xampl the flexibl xp n a'gre'ater proportion oranentirety of steel scrap, joint c p ings B between the nippl B and B.without a prohibitive fuel ratio or liability of It will be seen fromreference to Figures 1, 2 and freezing or bridging. Another'adva-ntageis S'that the pipesl; are cl sely dj nt he inner that the much smallerquantity of fuel required. Wallof the refractory liningA said refractoryV 15 results in less sulphur absorption, of paramount ing being e sod aat A t give om for importance in melting iron suitable for malleabilthem. Notwithstanding the close spacings of izing. The highertemperature, less, sulphur abhe 911F 53? h re i i he forms Shown in Fsorption, and high percentage of steel scrappos ures1 l tsufficientspacing between adjacent sible, enables the making ofpearlitic high p pes a d b tw n p p and the refractory v 2o '1 strengthiron, which could heretofore bemade lining to permit the heated gases ofcombustion only in an electric or air furnace with greatly in to contactallfsides of each pipe. At least a small creased fuel and investmentcosts. Otheradvarrquantity'of the-productsof combustion rises be tageswill appear from time to 'time'in the spectween and behind the pipes Bso that they are ification and claims. 7 heated to some extent on thesides and back as p 25 The present applicationis a continuation in wellas on theinner face which is in contact with part of my application,Ser. No. 371,156, filed on the descending charge and the burned gasespass- June 15, 1929. ing up'through it. The res'ult is a heating eiiect-I illustrate my invention more or less diagreater than if the pipeswere abutting or heated grammatically in the accompanying drawings," ononly the inside face. Furthermore, heating 30 *wherein 1 ,7 v the pipeson all sides reducesthe tendency to Figure 1 is a vertical sectionthrough a cupola Warpingand growth' on the front or inside face of myinvention, one half beingan outside eleva otthe pipes r H tion'; i Theheated air passes through the pipes B Figure 2 isahorizontalsectionon-the1ine2 2" through nipples B7 and 3 connected bythe H 35"of Figure 1; flexible connection BL'into the .hot air bustleFigure 3 is an enlarged horizontal section er pipe B f a a'partof-Figure 2; A J Communicating with :the hot air bustle pipe Figure 4 isa section similar to Figure '3 through B?" are the hot air down-comerpipes .C. In avariant form; 1 I orderto provide for expansion andcontraction 4 Figure 5is a detail of one of the tubes of Fig these pipesma have inte posdr t r any lire iand suitable flexible or" expansionconnection .0

Fi ur s 6 and are pa tial h rizont l's t The ends cofthe'pip'es'Ccornmunicate with the each through a n t m I wind-boxertuyere'bustle pipe C which may 7 Llke are q by k? S m connectdirectly,or through bootlet boxes C s 45 throughout the specification anddrawings; I with r s of tuyre's C5 C6 the'drawings A indicates "theshellR i i to One or more connecting pipes D may-extend of the cupola WhlChmay be supported onany f th h d b t h suitable frame'orsupportingstructure A withrpm 2 9 1 eirwor us is 0 t e itsbottomplate 2-pp-b ti g'1 g' 3.I-, hy': bustle (F whereby a contlolled fraction of the50 suitable closure means'may be providedffo'r the W t m be bymassed,permlttmg hole in the bottom plate A the detailsthereof: wlthmllmltse eee t i blast t aforming no part per se oifithepresentinvention'; i tureentering theituyeres. In order to control h ig shown at' A6 in 'F1gur "1A passage of air through the passages D, I may indicates'arefractoryliningfortheshellA: provide'any 'suitable'valve mechanism D Each '55- Inordftovpre'heatthanI employ hnysuit" 1 Such y e controlled manually but.I il- 11b lustrate diagrammatically any suitable thermostatic controlmember D Referring to Figures 4 and 5, I may employ instead of the pipes18 the pipes E of circular 5 cross-section. Each such pipe, as shown inFigure 5 has an upper integral nipple E and a lower nipple E which mayextend to any suitable fiexible or expansion couplings E G indicates thesand bottom for the coke bed. G indicates the melting zone and G: thecharging door.

Figure 6 illustrates a variant form in which the air passages H,corresponding to B of Figure 2, are bounded on two faces by. the arcs HH which may be concentric with the axis or center of the cupola. Thepassages are separated from each other by the arcuately walled spaces HFigure 7 illustrates another variant form, which the air passages orducts J are bounded by the generally plane surfaces walls J beingseparated by the plane walled passages J Preferably, as in the form ofFigures 2, 6 and 7, the

air passages B H or J, as the case may be, are

' separated from each other by passages of generally uniform width andare separated from the refractory lining A by spaces of generallyuniform width.

It will be realized that whereas I have deso; scribed and shown apractical and operative device, nevertheless many changes might be madein the size, shape, number and disposition of parts without departingfrom the spirit of my invention. I therefore wish my description anddrawings to be taken as in a broad sense illustrative and diagrammaticrather than as limiting me to my specific showing. In particular I wishto be understood that I do not limit myself to any particular size,shape or combination of parts except so far as I specifically limitmyself thereto in any individual claim.

' The use and operation of my invention are as follows:

' In employing my invention I pass the air blast of ablast furnace .orcupola through an air 'jacket or series of pipes set around the shaftintermediate the level of the melting zone and the charging door. Thelength and the location of these pipes may vary with the choice of mamterial and its possible heat resistance. Preferably they do not extendlower than two feet above the upper limit of the melting zone as defined as the point of greatest cutting' away of the refractory lining.This might be five or six 5 ,-feet above the upper level of the tuyeres.'If they are brought down lower it is at the expense of employing veryhighly heat resisting material for the pipes, with the consequentincrease in the initial investment and probably in the 6o; .maintenancecost. To raise their lower ends much above four feet above the meltingzone results in a decrease of efficiency.

An important feature of my invention is that by limiting the totalcross-sectional area of the ca -air passages shown at 13 I increasegreatly'the amount of heating effect obtainable from the maximum amountof surface it is possible to place within the cupola. At the same timethe heating area of the pipes or pipe walls is infik creased by theemployment of a plurality of in dividual pipes and passages and byadmission heater will run so, much hotter than with the the excess ofcarbon monoxide (CO) gas. Therethe. adequate exposed or heating wallarea is to great pressure loss, and hence with a saving in power inrunning the blower.

Taking the structure as shown for example in Figure 2, I illustrate thepassages 13 the preferred radial width of which is about 1/28 of theinside diameter of the general cupola passage defined by the inner wallsor faces of the members B In practice I find that a reasonable range ofvariation in this ratio is from 1/14 to 1/56 of the diameter of thecupola. As small a width as 1/56 is about as small as can be usedwithout getting an -excessive power consumption of the blower, andalthough the heating effect and fuel economy is better, it may usuallybe preferable 'to use a greater width of passage. On the other I findthat a width of passage greater than 1/14 of the inside diameter of thecupola, while resulting in a minimumof power consumption, reduces thepro-heat and fuel economy. Further, the metal of the presmaller ratios,that the maintenance cost is high.

In operation the cupola may be=made up with a sand bottom coke bed andcharges in the usual manner. When the blower starts its operation itforces air through the inlet pipe B. The cold air so supplied fills thebustle passage 13 and thence passes through the heat passages B Notethat the direction of travel of the air in the passages B is indicatedas parallel with and in the same direction of travel as the by-productsof combustion. This arrangement is preferred but I do not wish tobespecifically limited thereto except so far as I limit myself in myclaims. By passing the air along a path or paths parallel with theascending gases from the combustion, but passing the air in an oppositedirection to the direction of movement of such gases, a somewhatincreased pre-heating efficiency is obtained, but

at the expense of a greater deterioration of the materials and aresultant necessity of greater investment in heater pipe material ofgreater heat resistance. .As the air enters the relativelyrestrictedpassages B its velocity increases due to the smallcross-sectional area of the vertical sections of the heater pipes.Heated by its quick passage through the pipes B around which the burnedor burning gases are flowing, it issues through the nipples B B to thehot air bustle pipe C. It thence passes to the wind box C and thence tothe tuyeres C or C Inasmuch as it may be advantageous to control to someextent the temperature of the air I provide means, in?- cluding thepassages D and the valve D for -by-.. passing a certain proportion ofthe cold air from the bustle B to the wind box C .I find it advantageousto place the air heater sections or passages below the charging door.

'They are in a position where they are exposed to a practicallynonoxidizing atmosphere, due to fore they are relatively free from thescaling ofmaterial of low heat resistance which takes place inconstructions where the air heater sections are placed elsewhere. It isimportant to properly relate the length of the passages B to theircross-r sectional area in order thatthe rapidly moving air will passthrough a passage of sufficient lengthand with asufiicient exposed wallarea to get the desired heating effect. One method of obtaining heat allsides of the passages, as shown in the accompanying drawings; 1

One advantage, ofmy construction involving only one straight passa e ofthe air through heator elements parallel with the movement of thefurnace gases, is that it is possible to make the air heating elementswithout any joints exposed to the high temperature.

I claim:

1. In a hot blast cupola, a cupola member, an air blast inlet passage, aplurality of air preheating passages in communication therewith,positioned within said cupola, a charging door for said cupola, said airpreheating passages being located substantially below said charging doorand means for delivering the air to be pre-heated from said air blastsimultaneously to the same end of each of said pre-heating passages, aplurality of tuyres, and means for delivering heated air from theopposite ends of each of said preheating passages to said tuyres, theradial width of the passage being in the range of from 1/56 to 1/14 ofthe interior diameter of the cupola.

2. In a. hot blast cupola, a cupola member, an air blast inlet passage,a plurality of tuyeres and means for pre-heating air for delivery tosaid tuyeres, including a plurality of generally straight pre-heatingpassage members positioned within said cupola and in general parallelismwith each other, and means for maintaining a flow of air therethrough,in parallel, with a like direction of flow in all passages, the radialwidth of the passages being in the range of from 1/56 to l/14 of theinterior diameter of the cupola.

3. The structure of claim 2 characterized in that the pre-heatingpassage members are spaced from the inner wall of the cupola, the spacebetween the cupola and the passages being open for the passage of thehot gases through the cupola.

4. The structure of claim 2 characterized in that -the individualpre-heating passages are spaced from each other and from the inner wallof the cupola, the spaces between the individual passages, and betweenthe passages and the cupola being open for the passage of heated gasesthrough the cupola.

5. In a hot blast cupola, a cupola member, an air blast inlet passage,an air pre-heating passage in communication therewith, spaced withinsaid cupola and a charging door for said cupola, said air preheatingpassage being located substantially below the level of said chargingdoor and being spaced radially inwardly from the opposite inner face ofthe cupola, said passage having a radial width generally equivalent to1/28 of theinte rior diameter of the cupola, means for delivering theair to be pre-heated from the air blast to one end of the pre-heatingpassage, and means for delivering heated air from the opposite end ofthe passage to theinterior of the cupola.

6. In a hot blast cupola member, a charging door for said cupola,pro-heating air passage elements, which include a portion positionedwithin the cupola and centrally spaced inwardly from the opposite innerface of the lining and being located substantially below the level ofthe charging door, and integral angularly extending end portions at theends thereof extending outwardly through the cupola wall and removableflexible connection means associated with said ends, positionedsubstantially without the wall of the cupola.

7. In a hot blast cupola, a cupola member, a charging door therefor, arefractory lining therefor, pre-heating air passage members positionedwithin said cupola and being located substantially below the chargingdoor level and spaced inwardly from the opposite inner face of saidlining sufficient to define a gas passage of small but uniform widthbetween the inner face of the refractory lining and the opposed faces ofthe passages, the passage faces remote from the refractory lining beingadapted to contact the charge of the cupola, said passages beinggenerally rectilinear in axial extension, and parallel with the axis ofthe cupola, the radial width of the passages being in the range of from1/56 to 1/14 of the interior diameter of the cupola.

8. In a hot blast cupola, a cupola member having a charging door, an airblast inlet passage, a plurality of air heating passages incommunication therewith, positioned within said cupola member andlocated substantially below the charging door and spaced centrallyinwardly from the inner face of the cupola at that level, said passageshaving a radial width generally equivalent to 1/28 of the interiordiameter of the cupola, means for delivering the air to be pre-heatedfrom the air blast inlet passage to one end of the preheating passages,and means for delivering heated air from the opposite end of thepassages to the interior of the cupola.

9. In a hot blast cupola, a cupola member having a charging door, an airblast inlet passage,

a plurality of air preheating passages in communication therewith, andlocated substantially below the charging door, and spaced centrallyinwardly from the inner face of the cupola at that level, said passageshaving a radial width in the range of from 1/56 to 1/14 of the interiordiameter of the cupola, means for delivering air to be pre-heated fromthe air blast inlet to one end of the preheating passages, and means fordelivering preheated air from the opposite end of the passages to theinterior of the cupola, said air delivery means being adapted tomaintain a flow of air through said passage in parallelism with the pathof movement of the heated gases upwardly through the cupola, and in thesame direction.

ROGER, STUART BROWN.

